Payload accommodations systems typically have vents on the exterior of a payload launch vehicle designed generally to vent gases from the interior to the atmosphere during ascent. Simultaneously, during launch, it is also important to keep contaminants and moisture out of the payload launch vehicle, to keep cooling air inside and flowing properly in the payload launch vehicle, and to maintain the interior acoustic environment of the payload launch vehicle.
The traditional approach has been to use flapper valves in combination with internal acoustic baffles to address all of these issues. The flapper valves are used for venting and contaminant protection, while the internal baffles control the internal acoustic load. This approach suffers from at least three main problems. First, installation of the flapper valves and internal baffles can be complicated and time consuming. Additionally, because flapper valves and internal baffles are permanently attached to the payload launch vehicle, they add unnecessary weight to the payload and thus increase launch vehicle power requirements. Finally, the use of interior baffles changes the flow characteristics within the payload cavity.
A second approach to this problem has been to use lanyard release mechanisms. In this method, plugs are used to cover the vent holes. These plugs are connected to one another by a rope. Upon launch, the rope is cut releasing the plugs and uncovering the vents. This approach also has problems. First, it can be quite complicated to implement. Second, it is not as reliable as desired.
A third method is to use a louvered, open hole. However, the disadvantage of this method is that contamination control is not guaranteed.
Therefore, there exists a need for an ascent vent cover that addresses the above venting issues, is simple, lightweight and reliable and saves operational time.